1. Technical Field
The present invention relates to a system of measuring a warpage and a method of measuring a warpage.
2. Description of the Related Art
Recently, a demand for miniaturization and slimness of electronic products has increased. In order to meet the demand, attempts to make a substrate used as main parts of various electronic products smaller and thinner has continuously been conducted. Further, in order to implement high performance of electronic products, technologies for mounting active devices such as integrated circuit chips with high integration, and the like, and passive devices such as MLCC, inductor, and the like, in the inside or the outside of the substrate have been proposed.
Therefore, recently released package substrates have a duplex structure. Meanwhile, numerous micro circuit patterns are formed in the inside and outside of the package substrate and various electronic parts are embedded in the inside thereof or mounted on a surface thereof.
However, the complicated and slim package substrate products have reduced reliability due to a bending deflection phenomenon, that is, a warpage phenomenon according to the increase in temperature.
Therefore, a study for developing a technology of reducing the warpage, a technology of measuring how much the warpage is generated when the package substrate having a specific structure is exposed to the high temperature environment, and the like, have been conducted at various angles.
A representative method of the methods of measuring the warpage of the substrate may include a shadow moiré method introduced in Patent Document 1.
FIG. 1 is a diagram for describing a general measuring principle according to the related art that measures warpage using the shadow moiré method and FIG. 2 is a diagram schematically illustrating a fringe image.
Referring to FIGS. 1 and 2, an image reflected from a surface of a sample 2 by irradiating light using a light source 3 in the state in which a reference grating 1 arranged at a predetermined distance on a transparent quart panel and rendered as a reference line is disposed on a measuring sample 2 is acquired by a camera 4. In this case, the acquired image is formed with a fringe as illustrated in FIG. 2, such that it can measure how much the sample is warped based on the analysis of the fringe.
Meanwhile, in order to acquire the fringe image by using the shadow moiré method, light needs to be diffused-reflected from the surface of the sample.
Therefore, a sample pre-treating process is required in order to make the surface of the sample as the diffused reflection surface, which is performed by a process of thinly applying white spray on the surface of the sample.
However, the temperature of the sample is increased to about 260° C. by a heating plate 5, and the like, at the time of measuring the high temperature warpage. In this case, a fume is generated from a white spray material due to the high temperature.
The surface of the reference grating 1 is polluted due to the fume and thus, a contrast is the measured image is remarkably degraded, causing a problem in that the warpage cannot be accurately analyzed.